CDKN2A and adenoma: Moreover, we detected enriched protein levels of the senescent markers p15INK4b, p16INK4a and p27KIP1 (Supplementary Fig. 4), as well as in the occurrence of p16INK4a- and p19ARF-positive cells (Fig. 3I, J), therefore indicating that senescence is taking place in some of the adenoma cells.